Resizing a char[x] to char[y] at runtime

Question

OK, I hope I explain this one correctly. I have a struct:

typedef struct _MyData
{
   char Data[256];
   int  Index;
} MyData;

Now, I run into

Answer 1

You would re-arrange the structure like that

typedef struct _MyData
{
   int  Index;
   char Data[256];
} MyData;

And allocate instances with malloc/realloc like that:

my_data = (MyData*) malloc ( sizeof(MyData) + extra_space_needed );

This is an ugly approach and I would not recommend it (I would use pointers), but is an answer to your question how to do it without a pointer.

A limitation is that it allows for only one variable size member per struct, and has to be at the end.